(a) Field of Invention
The present invention relates to N-substituted cyclopeptide derivatives with antibacterial and antifungal activity and to a process for their preparation.
(b) Description of the Prior Art
A number of cyclic peptides have been either isolated from natural sources or prepared by classical synthetic methods, for example, see the review by E. Schroder and K. L. Luoke, "The Peptides;" Vol. II; Academic Press, New York, 1966, pp 424-478.
The present invention discloses novel cyclopeptide derivatives in which a nitrogen atom of the peptide back bone is substituted. These compounds have been found to have the desirable attributes of useful microbial activity coupled with a low order of toxicity.
In addition, a novel process for preparing N-substituted cyclopeptides is disclosed.